ECG monitoring in daily life is an important means of treating heart disease. To make it easier for the medical to monitor the ECG of their patients outside the hospital, we designed and developed an ECG monitoring an...ECG monitoring in daily life is an important means of treating heart disease. To make it easier for the medical to monitor the ECG of their patients outside the hospital, we designed and developed an ECG monitoring and alarming system based on Android smart phone. In our system, an ECG device collects the ECG signal and transmits it to an Android phone. The Android phone detects alarms which come from the ECG devices. When alarms occur, Android phone will capture the ECG images and the details about the alarms, and sends them to the cloud Alarm Server (AS). Once received, AS push the messages to doctors’ phone, so the doctors could see the ECG images and alarm details on their mobile phone. In our system, high resolution ECG pictures are transmitted to doctors’ phone in a user-friendly way, which can help doctors keep track of their patient’s condition easily.展开更多
With the development and utilization of renewable energy,the scaling of microgrid composed of distributed generation systems and energy storing devices,e.g,photovoltaic(PV),wind power,micro gas turbine,fuel cell,are b...With the development and utilization of renewable energy,the scaling of microgrid composed of distributed generation systems and energy storing devices,e.g,photovoltaic(PV),wind power,micro gas turbine,fuel cell,are becoming much lager.Research on control of multi-inverter parallel is the focus as the key technique,which can improve the reliability of microgrids.The inverters in the microgrid operate in parallel,which not only facilitates the expansion of the microgrid but also improves the reliability of the operation of the microgrid system in off-grid mode.The key to the parallel operation of the inverter is to achieve even distribution of the load current.In this paper,a comprehensive review on the control strategies of parallel-operated inverters is presented.Also,the detailed analysis,comparison,and discussion on the existing parallel control strategies are investigated.展开更多
This paper proposes an improved method for the prediction of radial vibration in switched reluctance motor(SRM)considering magnetic saturation.In this paper,the basic modeling principle is briefly introduced,it is bas...This paper proposes an improved method for the prediction of radial vibration in switched reluctance motor(SRM)considering magnetic saturation.In this paper,the basic modeling principle is briefly introduced,it is based on the derivation that the peak acceleration is dependent on the product of phase current and current gradient idi/dt.However,the derivation may cause errors due to saturation effect.Thus in this paper,the discrete sample data are firstly acquired based on DC pulse measurement method,by which electromagnetic,torque and peak acceleration characteristics can all be acquired.Then the entire peak acceleration characteristics are obtained by improved Least Square Support Vector Machine(LSSVM).Based on the obtained static peak acceleration characteristics,the time-varied radial vibration model is established based on superposition of natural oscillations of dominant vibration modes.Finally,a simulation model is built up using MATLAB/Simulink.The good agreement between simulation and experiment shows that the proposed method for modeling is feasible and accurate,even under saturation.In addition,since LSSVM does not need any prior knowledge,it is much easier for modeling compared with other existing literatures.展开更多
Current quality is one of the most important issues for operating three-phase grid-connected inverter in distributed generation systems. In practice, the grid current quality is degraded in case of non-ideal utility v...Current quality is one of the most important issues for operating three-phase grid-connected inverter in distributed generation systems. In practice, the grid current quality is degraded in case of non-ideal utility voltage. A new control strategy is proposed for the three-phase gridconnected inverter. Different from the traditional method,our proposal utilizes the unique abc-frame complex-coefficient filter and controller to achieve the balanced, sinusoidal grid current. The main feature of the proposed method is simple and easy to implement without any frame transformation. The theoretical analysis and experimental test are presented. The experimental results verify the effectiveness of the proposed control strategy.展开更多
Active damped LCL-filter-based inverters have been widely used for grid-connected distributed generation(DG) systems. In weak grids, however, the phase-locked loop(PLL) dynamics may detrimentally affect the stability ...Active damped LCL-filter-based inverters have been widely used for grid-connected distributed generation(DG) systems. In weak grids, however, the phase-locked loop(PLL) dynamics may detrimentally affect the stability of grid-connected inverters due to interaction between the PLL and the controller. In order to solve the problem, the impact of PLL dynamics on small-signal stability is investigated for the active damped LCL-filtered grid-connected inverters with capacitor voltage feedback. The system closed-loop transfer function is established based on the Norton equivalent model by taking the PLL dynamics into account. Using an established model, the system stability boundary is identified from the viewpoint of PLL bandwidth and current regulator gain. The accuracy of the ranges of stability for the PLL bandwidth and current regulator gain is verified by both simulation and experimental results.展开更多
An interesting inverter topology is proposed in this paper.It is similar to the typical three-phase full bridge inverter from the topology point of view,but smartly designed for the ground current reduction in single-...An interesting inverter topology is proposed in this paper.It is similar to the typical three-phase full bridge inverter from the topology point of view,but smartly designed for the ground current reduction in single-phase photovoltaic(PV)inverter applications.Theoretical analysis is conducted to clarify the operation mechanism of the proposed topology.Performance evaluation is carried out to verify the effectiveness of the proposed topology for the ground current suppression.展开更多
It is a well known fact that pulse width modulation(PWM)produces sideband effects.Taking this point into account,the accuracy of the grid-connected inverter model can be improved.In this paper,considering the aliasing...It is a well known fact that pulse width modulation(PWM)produces sideband effects.Taking this point into account,the accuracy of the grid-connected inverter model can be improved.In this paper,considering the aliasing effect of the PWM sideband components on the closed-loop control,a complete representation for the transfer function of the PWM is obtained.Furthermore,a multi-frequency model of grid-connected inverter system is derived.It is convenient for obtaining a PWM gain for grid-connected inverter system,which is PWM-controlled.In order to have an easy physical expression of the effects caused by the sideband components,an approximation is applied to simplify the PWM gain.The stability analysis is used to prove that PWM gain considering PWM effect is more precise than the conventional one.Experimental results verify the effectiveness of our proposal.展开更多
An effective vaccine for human immunodeficiency virus(HIV) is urgently needed to prevent HIV infection and progression to acquired immune deficiency syndrome(AIDS). As glycosylation of viral proteins becomes better un...An effective vaccine for human immunodeficiency virus(HIV) is urgently needed to prevent HIV infection and progression to acquired immune deficiency syndrome(AIDS). As glycosylation of viral proteins becomes better understood, carbohydrate-based antiviral vaccines against special viruses have attracted much attention. Significant efforts in carbohydrate synthesis and immunogenicity research have resulted in the development of multiple carbohydrate-based HIV vaccines. This review summarizes recent advances in synthetic carbohydrate-based vaccines design strategies and the applications of these vaccines in the prevention of HIV.展开更多
Integrating the electric vehicle into grid or microgrid has been receiving more and more attention in recent years.Typically,the electric vehicle(EV)chargers with their power batteries have been developed for vehicle-...Integrating the electric vehicle into grid or microgrid has been receiving more and more attention in recent years.Typically,the electric vehicle(EV)chargers with their power batteries have been developed for vehicle-to-home(V2H)applications,acting as a backup generation to supply emergency power directly to a home.Traditional EV chargers in V2H applications mainly consist of DC/DC and DC/AC stages,which complicate the control algorithm and result in low conversion efficiency.In order to solve this problem,a novel EV charger is proposed for V2H applications.It can boost the battery voltage and output AC voltage with only one-stage power conversion.Also,the DC,1-phase and 3-phase loads can be fed with the proposed single-stage EV charger.The system control strategy is also provided to deal with versatile load variations.Finally,the performance evaluation results verify the effectiveness of the proposed solution.展开更多
文摘ECG monitoring in daily life is an important means of treating heart disease. To make it easier for the medical to monitor the ECG of their patients outside the hospital, we designed and developed an ECG monitoring and alarming system based on Android smart phone. In our system, an ECG device collects the ECG signal and transmits it to an Android phone. The Android phone detects alarms which come from the ECG devices. When alarms occur, Android phone will capture the ECG images and the details about the alarms, and sends them to the cloud Alarm Server (AS). Once received, AS push the messages to doctors’ phone, so the doctors could see the ECG images and alarm details on their mobile phone. In our system, high resolution ECG pictures are transmitted to doctors’ phone in a user-friendly way, which can help doctors keep track of their patient’s condition easily.
文摘With the development and utilization of renewable energy,the scaling of microgrid composed of distributed generation systems and energy storing devices,e.g,photovoltaic(PV),wind power,micro gas turbine,fuel cell,are becoming much lager.Research on control of multi-inverter parallel is the focus as the key technique,which can improve the reliability of microgrids.The inverters in the microgrid operate in parallel,which not only facilitates the expansion of the microgrid but also improves the reliability of the operation of the microgrid system in off-grid mode.The key to the parallel operation of the inverter is to achieve even distribution of the load current.In this paper,a comprehensive review on the control strategies of parallel-operated inverters is presented.Also,the detailed analysis,comparison,and discussion on the existing parallel control strategies are investigated.
基金This work was supported by the National Natural Science Foundation of China under Grant 51277026 and 61674033Natural Science Foundation of Jiangsu Province under Grant BK20161148the Scientific Research Foundation of Graduate School of Southeast University under Grant YBJJ1822.(Corresponding author:Weifeng Sun.)。
文摘This paper proposes an improved method for the prediction of radial vibration in switched reluctance motor(SRM)considering magnetic saturation.In this paper,the basic modeling principle is briefly introduced,it is based on the derivation that the peak acceleration is dependent on the product of phase current and current gradient idi/dt.However,the derivation may cause errors due to saturation effect.Thus in this paper,the discrete sample data are firstly acquired based on DC pulse measurement method,by which electromagnetic,torque and peak acceleration characteristics can all be acquired.Then the entire peak acceleration characteristics are obtained by improved Least Square Support Vector Machine(LSSVM).Based on the obtained static peak acceleration characteristics,the time-varied radial vibration model is established based on superposition of natural oscillations of dominant vibration modes.Finally,a simulation model is built up using MATLAB/Simulink.The good agreement between simulation and experiment shows that the proposed method for modeling is feasible and accurate,even under saturation.In addition,since LSSVM does not need any prior knowledge,it is much easier for modeling compared with other existing literatures.
基金supported by the National Natural Science Foundation of China(No.51307149)
文摘Current quality is one of the most important issues for operating three-phase grid-connected inverter in distributed generation systems. In practice, the grid current quality is degraded in case of non-ideal utility voltage. A new control strategy is proposed for the three-phase gridconnected inverter. Different from the traditional method,our proposal utilizes the unique abc-frame complex-coefficient filter and controller to achieve the balanced, sinusoidal grid current. The main feature of the proposed method is simple and easy to implement without any frame transformation. The theoretical analysis and experimental test are presented. The experimental results verify the effectiveness of the proposed control strategy.
基金supported by Science Foundation for Distinguished Young Scholars of Hebei Province(No.E2016203133)Hundred Excellent Innovation Talents Support Program of Hebei Province(No.SLRC2017059)
文摘Active damped LCL-filter-based inverters have been widely used for grid-connected distributed generation(DG) systems. In weak grids, however, the phase-locked loop(PLL) dynamics may detrimentally affect the stability of grid-connected inverters due to interaction between the PLL and the controller. In order to solve the problem, the impact of PLL dynamics on small-signal stability is investigated for the active damped LCL-filtered grid-connected inverters with capacitor voltage feedback. The system closed-loop transfer function is established based on the Norton equivalent model by taking the PLL dynamics into account. Using an established model, the system stability boundary is identified from the viewpoint of PLL bandwidth and current regulator gain. The accuracy of the ranges of stability for the PLL bandwidth and current regulator gain is verified by both simulation and experimental results.
基金This work was supported by the National Natural Science Foundation of China(51307149)China Postdoctoral Science Foundation(2014M551050)Specialized Research Fund for the Doctoral Program of Higher Education(20131333120016).
文摘An interesting inverter topology is proposed in this paper.It is similar to the typical three-phase full bridge inverter from the topology point of view,but smartly designed for the ground current reduction in single-phase photovoltaic(PV)inverter applications.Theoretical analysis is conducted to clarify the operation mechanism of the proposed topology.Performance evaluation is carried out to verify the effectiveness of the proposed topology for the ground current suppression.
基金This work was supported by the National Natural Science Foundation of China(51677161)Natural Science Foundation of Hebei Province(E2019203563).
文摘It is a well known fact that pulse width modulation(PWM)produces sideband effects.Taking this point into account,the accuracy of the grid-connected inverter model can be improved.In this paper,considering the aliasing effect of the PWM sideband components on the closed-loop control,a complete representation for the transfer function of the PWM is obtained.Furthermore,a multi-frequency model of grid-connected inverter system is derived.It is convenient for obtaining a PWM gain for grid-connected inverter system,which is PWM-controlled.In order to have an easy physical expression of the effects caused by the sideband components,an approximation is applied to simplify the PWM gain.The stability analysis is used to prove that PWM gain considering PWM effect is more precise than the conventional one.Experimental results verify the effectiveness of our proposal.
基金the National Science Foundation for Young Scientists of China(No.21302068)the Natural Science Foundation of Jiangsu Province,China(No.BK20130127,BK20140154,and BK20150140)+1 种基金the Public Health Research Center at Jiangnan University(No.JUPH201502)Key Laboratory of Carbohydrate Chemistry and Biotechnology Ministry of Education,Jiangnan University(KLCCB-KF201504)
文摘An effective vaccine for human immunodeficiency virus(HIV) is urgently needed to prevent HIV infection and progression to acquired immune deficiency syndrome(AIDS). As glycosylation of viral proteins becomes better understood, carbohydrate-based antiviral vaccines against special viruses have attracted much attention. Significant efforts in carbohydrate synthesis and immunogenicity research have resulted in the development of multiple carbohydrate-based HIV vaccines. This review summarizes recent advances in synthetic carbohydrate-based vaccines design strategies and the applications of these vaccines in the prevention of HIV.
基金Supported by Hebei Province Natural Science Foundation(E2015203407)Young Scholars Research Project of Yanshan University(15LGB011).
文摘Integrating the electric vehicle into grid or microgrid has been receiving more and more attention in recent years.Typically,the electric vehicle(EV)chargers with their power batteries have been developed for vehicle-to-home(V2H)applications,acting as a backup generation to supply emergency power directly to a home.Traditional EV chargers in V2H applications mainly consist of DC/DC and DC/AC stages,which complicate the control algorithm and result in low conversion efficiency.In order to solve this problem,a novel EV charger is proposed for V2H applications.It can boost the battery voltage and output AC voltage with only one-stage power conversion.Also,the DC,1-phase and 3-phase loads can be fed with the proposed single-stage EV charger.The system control strategy is also provided to deal with versatile load variations.Finally,the performance evaluation results verify the effectiveness of the proposed solution.
